Signal-operated repeater circuits



July 23, i929 H. W. DUDLEY l LZZDQSS SIGNAL OPERATED REPEATER CIRCUITSoriginal Find Dec. s1. 192e Hg z Patented July l 23, 1929.

UNITED STA-Tas PATENT OFFICE.

HOHER W. DUDLEY, OF BROOKLYN, NEW 4YORK, ASSIGNOB TO BELL TELEPHONELABORATORIES, INCORPORATED, OF NEW YORK1\l'.K Y., A CORPORATION OF NEWYORK.

SIG-NAL-OEIERATEl) BEPEATER CIRCUITS.

Application iled December 31, 19255, Serial No. 158,195. Renewed April25, 1928.

This invention relates to signal operated' repeater circuits in whichone-way repeaters are arranged to be automatically pomted in thedirection in which signal Waves are b'eing transmitted over a two-wayline.

An object of the invention is to simpllfy signal operated repeatercircuits.

Another object of the invention 1s to provide an improved signaloperated repeater circuit for use between relatively noisy andrelatively quiet signal lines.

Heretofore, so-called signal or voice operated repeater circuits havebeen of two general types, one, the so-called biased type 1n which arepeater is left in condition to transmit-.eciently only in thedirection in which it last transmitted until transmission in the otherdirection is initiated, and the other, the so-called neutral type inwhich, between periods of transmission, the repeater is not 1n conditionto transmit ehciently in either direction.

In accordance with a feature of this invention, there is provided arepeater which 1s normally pointed in one direction, regardless of thedirection in which transmission last took place, but which is pointed inthe other direction when transmission in that direction is initiated.

In accordance with another feature of this invention, several repeatersof the above type are employed in a transmission circuit, part of thembeing pointed normally in each direction so that no matter in whichdirection wavesl are to be transmitted, only a part of the nepeaterpointing circuits will have to be operated to put the entire system inoperation.

The repeater circuit of this invention is of the biased type fortransmission'in one direction and of the neutral type for transmissionin the other direction so that it is well fitted for use in atransmission system in which the conditions are such that one type isbest suitedfor transmission in one direction while the other type isdesirable for transmission in the other direction. For example, it iswell suited for connectingI a relatively quiet' line to a relativelynoisy line in which case it is connected so as to normally transmitwaves from the quiet line to the noisy line. s When used in thls manner,the signal operated circuit at the output of the repeater will not haveto maint-ain so great a margin against amplilied noise.

. impresse in addition, un, @nena of this invention.

is very simple and requires only one amplifier and one delay circuit.

This invention can be more readily understood by reference to thefollowing detailed description in connection with the drawing in which:

Fig. 1 shows diagrammatically one embodiment of the invention, and

Figs. 2 and 3 show two transmission systems employmg repeater circuitsof the type shown in Fig. 1.

Referring .to Fig. 1, there is shown a repeater circuit having westterminals 4 and east terminals 5. There is provided a repeater oramplifier 6 which is preferably of the vacuum tube type. This amplifieris so connected to the terminals 4 and 5 that transmission from west toeast may take place without any change in the transmission circuit.Relays 7 and 8 are provided for pointlng the repeater in the oppositedirection when transmission from east to west is initiated. The windingsof these relays are con-- nected to the output of an amplifier-rectifier9, the input of which is connected to the terminals 5. rlhe operation ofrelay 7 also opens the input circuit of a second amplifier-rectiier 10which has a relay 11 connected to its output circuit for opening theinput circuit of the amplifier-rectifier 9 when transmission from westto east is taking place. A delay network 12 is connected between theterminals 5 and the contacts of relay 8 so that the transmission ofwaves from east to west is delayed until the relays 8 and 7 have hadsuticient time to operate to point the ampliier 6 in the properdirection.' 'lhis network also delays the transmission from west to eastfor suiicient time to permit the operation of relay 11 to' open thecircuitsupplying relays 7 and 8.

" Thus', waves impressed on the west terminals 4 are directlytransmitted through the aliiplier 6 and at the same time a portion ofthe energy impressed on the west terminals is transmitted through aseparate circuit to energize the amplifier-rectier 10 to operate Vtherelay 11. The relay 11 opens the input circuit of the am liier-recter 9so that it can not be energize by the amplifier waves in the out ut ofthe amplifier 6. Also, waves 'on the east terminals 5 energize theamplifier-rectifier 9 to operate relays 7 and 8 repointing the amplifier6 to transmit waves `from east to west and opening the input circuit ofthe amplifier-rectifier 1() so that it will not be affected by theamplified waves.

If any correcting networks or filters are required for transmission inboth directions, p

they may be included as part of the amplifier circuit 6l unless they areof value as delay circuits in which case they should be inserted inplace of or as a part of the network 12. If itis desired to transmitwith unequal efliciency in the two directions, appropriate networks for.transmitting from westy to east may be inserted in the input leads 13 orthe output leads 14, and appropriate networks for transmitting from eastto west may be connected in the Ainput leads 15 or the output leads 16,as desired.

With the type of circuit described, no time is lost for transmissionfrom west to east, but transmission in the opposite direction requiressome time for operation of the relays. On the other hand, the relays 7and 8 normally connected to the output of the amplifier must maintain amargin against amplified noise, so that noise on the west line,amplified by the amplifier 6, will not operate them.

With regard to the time of operation, the disadvantages may be overcomein a transmission system by pointing alternate repeaters in oppositedirections so that, for the system as a whole, transmission in eitherdirection will only require the operation of one half of the repeaters.a noisy line is to be connected to a quiet line, a repeater of this typepresents certain definite advantages as hereinafter described.

Fig. 2 shows a transmission system for transmitting between a station Aand a station B. The system comprises a relatively quiet section of line20 connectedbetween two relatively noisy sections of lines 21 and 22.Repeaters 23 and 24, which are the type shown in Fi 1, are connectedbetween the line 20 andt e lines 21 and 22, respectively. As indicated,these repeaters are connected in such a Vway that transmission normallytakes place from the quiet line to the -noisy lines and for transmissionin the opposite direction they must be repointed.- In this way no strict'requirements as to-margin againstamplified noise are placed upon therelays connected to the output of the amplifiers. The quiet line might,for example, be a section of submarine cable of such length orattenuationthat a sufiiciently accurate balance to obtain the necessaryhigh gain with the standard type of repeater could not be provided.

Fig.'3 shows a similar system in which repeaters 26 and 27 are connectedbetween a noisy line 28 and two relatively quiet lines 29 and 30,respectively. Inthis system, as indicated, the repeaters are so.connected as to normally transmit from the quiet lines to In situationsin which.

, In the systems of both Figs. 2 and 3 transmission in either directionrequires the operation of the printing circuit of only one reeater.

What is claimed is: f f

1. In a two-way signaling circuit, a oneway repeater normally connectedto transmit waves in one direction, means responsive to waves in theother direction for pointing said repeater toamplify waves in thatdirection, and means responsive to waves being transmitted in said onedirection for making said first means inoperative.

2. A combination according to the preceding claim, and a delay circuitcommon to a portion of said signaling circuit traversed by the wavestransmitted in either direction therein, and located so as to preventtransmission of the waves in said one direction to the first mentionedmeans until the second mentioned means has operated, and to preventtransmission of the waves in said other direction to said repeater untilthe first mentioned means has operated.

3. In combination, a plurality of twoway l way repeater, and means fornormally v connecting said repeater to transmit waves in one directionand for automatically pointing said repeater in the opposite directionin response to waves being transmitted in that direction, substantiallyhalf of said repeater circuits being connected so as to normallytransmit waves in one direction and the remainder of said repeatercircuits being connected so as tonormally transmit waves in the.opposite direction.

4. In combination, a relatively quiet twoway signaling line, arelatively noisy twoway signaling line, a one-way repeater connectedbetween4 said lines and operative al,-

ways in the absence of signaling transmission in either direction insaid lines, and for signaling transmission in the direction from saidquiet line to said noisy line, to transmit waves from said quiet line tosaid noisy line andmeans for pointing said repeater in the oppositedirection in response to signaling waves from said noisy line.

5. In combination, a pair of two-way transmission lines, a one-wayrepeaterA normally connected to transmit waves from one of said lines tothe other, a relay responsive to waves from said other line for pointingsaid repeater in the opposite direction, and a second relay responsiveto waves from said rst line for making said first relay inoperative,said second relay being made inoperative by the action of said firstrelay.

6.`A combination according to the preceding claimj in which a delaycircuit is connected between the point in said other line to Which saidfirst relay is connected and said repeater.

7. In a two-Way signaling circuit, a one- Way circuit normally connectedto transmit Waves in one direction, means responsive to waves in theother direction for pointing said one-Way circuit to transmit Waves inthat direction, and means responsive to Waves being transmitted in saidone direction for making said first means inoperative.

8. In combination, a pair of two-Way transmission lines, a one-Waycircuit normally one-Way circuit in the opposite direction, andv asecond relay responsive to Waves from said one line for making the firstmentioned relayu inoperative, said second relay being made inoperativeby the action of said rst mentioned V relay.

In Witness whereof, I hereunto subscribe I my name this 29th day ofDecember A. D. 1926.

HOIWER W. DIIDLEY. I

